1. Field of the Invention
This invention relates to a rapid transit system and more particularly to a rapid transit system for the mass transportation of passengers by the continuous movement of vehicles upon rails of an exclusive roadway that forms an endless transit loop.
2. Description of the Prior Art
Modern mass transit systems are well known in the art and are characterized by the automatic or attended operation of vehicles either singly or in multiple vehicle trains on an exclusive roadway in the form of a continuous loop having stations for passenger boarding and departing located at selected points in the loop. The roadway may comprise either single or double track sections elevated or located at grade level. The track sections may be supported by steel guide beams on concrete slabs for steering the vehicle on the roadway. The vehicles or multi-vehicle trains may be propelled by power rails or inductive wires feeding electric current to the electric motors of the vehicles. The transit systems generally include a guidance system which serves to maintain stability of the vehicles as they move from station to station on the exclusive roadway in the continuous loop.
Fully automated transit systems, such as the rapid transit system built by the San Francisco Bay Area Rapid Transit District (BARTD) and the Experimental Transit Expressway erected by Westinghouse Company in Allegheny County, Pennsylvania, operate vehicles singly or in multiple-vehicle trains at preselected intervals unidirectionally over an exclusive roadway. The experimental Transit Expressway is disclosed in The American Society of Mechanical Engineers, publication No. 67-WA/BHF-8, entitled An Evaluation of an Automated Mass Transit System in which rubber tired vehicles ride on concrete track slabs and are steered through vehicle guidance systems that follow a steel guide beam centered down the track of the roadway. Vehicle current collectors pick up power from energized rails located adjacent the track slab. Intelligence is conveyed to and from the vehicles by conductor wires laid along the inside of the track slab. With this arrangement the operation of the entire system is monitored and controlled remotely from a control center through electrical equipment located at the respective stations along the roadway and aboard the vehicles. A built-in-system of checks and interlocks operate to continuously monitor the system operation to detect malfunctions or failures in equipment. In the event of a malfunction or failure in equipment, all the vehicles are brought to a halt by an emergency stop procedure. Nevertheless, in the event a vehicle becomes disabled on the roadway, it is necessary to place operators on board to recover the vehicle.
U.S. Pat. No. 3,403,634 illustrates and describes an automatic transportation system having vehicles remotely controlled for effecting vehicle traffic between stations. This system includes a closed main loop arrangement with the vehicles traveling at a substantially uniform speed and automatically switched to and from preselected stations located on spur loops so that the traffic on the main loop is undisturbed. The enclosed loop comprises a stationary tubular elongated endless conduit that is adapted to be supported adjacent present transportation facilities. Vehicles run bumper to bumper in the closed loop at a generally high rate of speed with a minimum of space between the vehicles as determined by the demand placed upon the system. A car or vehicle may enter the main loop from a spur loop. A pair of longitudinal rails extend through the closed loop and include a C-shaped cross section. Rubber tired wheels of the vehicles engage the C-shaped rails. Rotation of the wheels through a drive means propels the vehicles on the tracks within the enclosed conduit loop. The drive mechanism comprises a squirrel cage induction motor having stator windings employed along the track and continuously excited by current therethrough to generate a magnetic wave which actuates a rotor of the motor placed on the vehicle to rotate the tires through the axle and provide constant thrust to the vehicles.
There is need for the mass transportation of passengers of vehicles that operate over an exclusive roadway in the form of a continuous loop. While it has been suggested to provide elaborate fully automated mass transit systems, the safeguards required for such a system render the system commercially unfeasible. Thus a mass transit system is needed that satisfies the problems presented by modern urban-suburban commutation in a safe and efficient manner but economically feasible.